leak sanitizer can not show backtrace

[Dushistov]

After end of program leak sanitizer show:

==11566==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 8 byte(s) in 1 object(s) allocated from:
#0 0xb883b8 in __interceptor_malloc /media/Seagate_Expansi/tmp/llvm-svn/src/llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:52
#1 0x7f6fb41173a9 in read_charset_define /home/evgeniy/arch_build/libx11/src/libX11-1.6.3/src/xlibi18n/lcGeneric.c:505
#2 0x7f6fb41173a9 in load_generic /home/evgeniy/arch_build/libx11/src/libX11-1.6.3/src/xlibi18n/lcGeneric.c:940

Direct leak of 7 byte(s) in 1 object(s) allocated from:
#0 0xb883b8 in __interceptor_malloc /media/Seagate_Expansi/tmp/llvm-svn/src/llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:52
#1 0x7f6fb4111e6f in _XlcAddCT /home/evgeniy/arch_build/libx11/src/libX11-1.6.3/src/xlibi18n/lcCT.c:517

SUMMARY: AddressSanitizer: 15 byte(s) leaked in 2 allocation(s).

As you can see after _XlcAddCT leak detector do not show rest of backtrace.
If compile _XlcAddCT into shared library and LD_PRELOAD it and print backtrace with
backtrace(3), then I get something like this:
backtrace() returned 20 addresses
./a.out(__interceptor_backtrace+0x41) [0xb17071]
/home/evgeniy/projects/compas/planetable/km_pl/build_sanit/libx11_preload.so(_XlcAddCT+0x60) [0x7fa42e9948a0]
/usr/lib/libX11.so.6(_XlcInitCTInfo+0x34) [0x7fa42d9610c4]
/usr/lib/libX11.so.6(+0x573d3) [0x7fa42d9673d3]
/usr/lib/libX11.so.6(+0x56a73) [0x7fa42d966a73]
/usr/lib/libX11.so.6(_XlcCreateLC+0x3c) [0x7fa42d9672ac]
/usr/lib/libX11.so.6(_XlcUtf8Loader+0x10) [0x7fa42d9880d0]
/usr/lib/libX11.so.6(_XOpenLC+0x10e) [0x7fa42d96e87e]
/usr/lib/libX11.so.6(_XrmInitParseInfo+0xb) [0x7fa42d96ea8b]
/usr/lib/libX11.so.6(+0x467b0) [0x7fa42d9567b0]
/usr/lib/libX11.so.6(XrmGetStringDatabase+0xe) [0x7fa42d959dce]
/usr/lib/libX11.so.6(+0x26774) [0x7fa42d936774]
/usr/lib/libX11.so.6(XGetDefault+0x10e) [0x7fa42d936a1e]
./a.out() [0x245d9cb]
./a.out() [0x2460578]
./a.out() [0x23d9eaa]
./a.out() [0x23d9a3c]
./a.out(main+0x290f) [0x21871bf]
/usr/lib/libc.so.6(__libc_start_main+0xf0) [0x7fa42aa91710]
./a.out(_start+0x29) [0xae6de9]

also if rebuild application without -fsanitize=address,undefined and run under valgrind it show full backtrace for memory leak.

This bug prevent me to mask this memory leak with "leak:XGetDefault"

[Dushistov]

I try with clang 3.9.0(trunk) and gcc 5.3.0. Platform linux/amd64

[yugr]

Check https://github.com/google/sanitizers/wiki/AddressSanitizer ("My malloc stacktraces are too short?" section).